Ok, I'm still very new here and did a search and found bits and pieces about these but I'd like to know what you use. I'm going to be doing some engraving in some small parts and would like to create a jig block with a cavity to hold them with a vacuum pump system to get away from taking the time to screw each one down to a block or use a double face tape.

I'd love to see pics of your setups, construction and/or hear about your success or lack of with these. If I have posted this in the wrong area, possibly you could direct me to the right place...this form is huge!

Many thanks-


EDIT: Well I see there is a workholding forum so please feel free to move this. Sorry 'bout that-

Go to joewoodworker.com Anything you want to know about vacuum work holding is there.

Thanks for asnwering and yes, I've been there but saw no "nesting" type setups, only veneering setups and vacuum tables. Possibly I missed it?

I'd love to see pics of your setups, construction and/or hear about your success or lack of with these.



Look at this link for my effort.

http://www.cnczone.com/forums/showthread.php?t=34537

Also do a search on the forum for vacuum. You will see a few threads with different ideas.

Greg

Look at this link for my effort.

http://www.cnczone.com/forums/showthread.php?t=34537

Also do a search on the forum for vacuum. You will see a few threads with different ideas.

Greg

Actually Greg, you have inspired me already before you posted here, lol! I saw some of your videos on youtube and have enjoyed learning from them. The link you provided clears up all the questions I had for you so thank you very much for your time and info.

Specifically I'm looking at making nesting fixtures that have the shape of each part that I'll be engraving and those will be interchangable on top of a main vacuum housing. If that makes any sense. lol!

Specifically I'm looking at making nesting fixtures that have the shape of each part that I'll be engraving
and those will be interchangable on top of a main vacuum housing. If that makes any sense. lol!

This makes perfect sense to me. If I was doing similar repeat jobs I would do exactly this.

I can imagine the fixture having a common base with the vacuum connection. This would stay fixed to the table.

Then having job specific fixtures that fit onto the common base with positive location and seal.

Each of these fixtures would then have the job specific shape of seal and appropriate locating dowels or shoulders etc. to locate and hold that particular job.

Both base and fixture together would not need to be more than 20 to 30mm high.

In the right situation this would be well worth pursuing. Good idea. :cheers:

Greg

Just so happens I'm working with a vacuum plate now . may be able to get some pics of it . New here and have my own problem with a machine . Basically , took a 1" thk. plate that I could shape my profile in and room for some plumbing parts . rectangle say 5" X 7 " . my parts have two small cavities in bottom so I cut into my plate the depth needed , ( +.003 ) on profile , don't want to much play. and gave myself another (.030) wall offset of that profile and put in a o-ring . So I have 2 profile pockets and a o-ring profile close to shape .

Added 4 more smaller ( .375 ) dia. in 4 corners . took plate out and started drilling 1/4" dia holes to intersect where the o-rings are. plugged in ( 3 ) 1/4" pipe taps ( 2 ) in one side ( 1 ) in the other . Used plastic 90 deg elbows and some plastic hose that fit the couplings.. Also bought a tank from msc . To suck any coolant I may get and put a relief valve in it .. I cant believe the time i have saved on this set up .

I have a old vacuum pump that gets something like 24 lbs of vac.
It holds parts taking (.400 ) dp cuts and 25 " fd rate and hold them flat .
Crazy . Very in expensive to thing we spent maybe $300 in materials .

Hope this gives you some new thoughts on how this may work for you.

Tony

Got any pics Tony.

Always easier to understand the description. :)

Greg

Yes, Tony, that is exactly what I was looking to do and using O rings was the same idea I had as well since I'll be working with fairly small parts (no bigger than 3" X 3").

As Greg mentioned, if you ever do get any pics I'd love to see them.

Welcome to the forum and thanks so much to you guys for your help- :)

when i make vacume fixtures I make a scroll (spiral) in the pockets pending thickness of the material for the spacing of the walls. then on the outside (not connected) cut an oring groove. The groove will take a few trys on exact depth, I found that 40 - 80 durometer?? type o-ring to work the best. Also I only have a crush depth of a .005-.010 as if two much will not flatten down. also place a vacume in the center via cross drill.The magic vacume numbers seem to be 27 + inches an automitve airtype vacume pump works great as coolant does not seem to effect it. it does however require lots of shop air.

hope this helps.

when i make vacume fixtures I make a scroll (spiral) in the pockets pending thickness of the material for the spacing of the walls. then on the outside (not connected) cut an oring groove. The groove will take a few trys on exact depth, I found that 40 - 80 durometer?? type o-ring to work the best. Also I only have a crush depth of a .005-.010 as if two much will not flatten down. also place a vacume in the center via cross drill.The magic vacume numbers seem to be 27 + inches an automitve airtype vacume pump works great as coolant does not seem to effect it. it does however require lots of shop air.

hope this helps.

Thanks, it did help but may I ask you to be a little clearer on this sentence?

it does however require lots of shop air.
It's a vacuum pump, no?

Any chance you might have a pic or 2 of the setup?

Thanks again!

I think he's using an air powered venturi vacuum generator.

Ah, I see, thank you sir-

Ok guys ,

Took pictures today and lets see if I can show you what I did.

Not sure if I can write once pics are up so bear with me . 1st time sending pics.
Basically I made up my fixture plate to hold part, Attached some plumbing to it to a pump and tank so as i could release pressure and hold vac from take. if that makes any sense. Pics hopefully are in order of hook-up.

Here goes. ALSO SORRY ABOUT PIC'S SAVED AS CHRISTMAS 2007 . DOWNLOADED ALL THE SHOTS ON CAMERA AND NAMED THEM THE SAME FOR EVERYTHING.

Hopefully you can see how i made if you can enlarge the shots. Tank has to hose fittings at top of tank , one goes to the release valve that i made and mounted on table in machine. 2nd goes to pump. The pump is on floor and (1) hose from it to tank. The pump is old and when we tried to figure how much suction we could get we got like it was equal to a 33 lb weight on part. Didn't sound like much and may even be wrong all together. BUT all I can say is we wittle out parts faster and flater that we could before . WE also changed to Carbide 3 flute high helix , running twice as fast than before and feed rate about 30% more.

These things work,
Hope this helps .

air powered venturi vacuum generator.
is right.


sorry about that

looks nice do the o-rings flatten down all the way???

Excellent pics, thanks for putting them up for us. As was asked above, I'm thinking since O rings are fairly "solid" and don't compress much, you probably only have them a couple of thousandths above the surface?

Thanks again-

Plenty of O ring alternatives at www.allstaradhesives.com

Thanks for link, Gerry :)

Not sure if you can notice but I recessed the cavity deeper in sections of o-rings and spun some .100 dia. bosses in few areas to help keep from sucking down . the o-rings only collapse .01 works out fine . ok guys glad I could help .
Stay cool , see ya around the old forum.

Tony
A & M Machine
Middletown DE

Just curious. Why do you use o-ring material instead of suction cups from Piab or other manufactures? The suction cups will collapse down so you can locate on the fixture not the o-ring. But I can see that by using o-ring material you can get more surface area to hold down the part, instead of just placing a couple of suction cups.

If you get your groove the right depth, the o-ring or tubing will suck down and the part will be flush with fixture.

Hey Guy's, heres another option perhaps?

Depending on your setup you may be able to get by with vacuum grooves and a light coating of high vacuum grease around the perimeter of your fixture instead of O-rings. Don't forget to indicate the top of your piece to be engraved to see if it's level.

I have used it for other fixtures at work and a little goes a long way. In sizing your grooves think I think in terms of volume and try not to choke it down anywhere in the system so you get a quick pull. I have found using a tank and valves in the system helps a lot also.

Good Luck,

Ferny.

So is it a performance reason or cost why you choose o-ring material over suction cups? I've always used Piab cups on my vacuum fixtures but I read this post and it got me thinking about trying this approach. Also how long of life do you get out of the o-ring stock? We can get about 100,000 part out of the suction cups before they start to leak and break down because of the collant oils and small aluminum chips.

Where I used vac fixtures was in the aerospace manufacturing. We cut our grooves to match the profile of the part. If a part had holes or cutouts you can put grooves around those also. That way you can drill or cut thru without losing suction.

Do the cups work on curved surfaces or only flat surfaces?

We had some fixtures that had curved surfaces that matched a surface of the part (4 & 5-axis machines)

We used surgical tubing.... I don't think we got anywhere close to 100,000 parts.

I'm using them on flat surfaces only.